Ansible has the option to run playbooks via sudo. You can setup passwordless sudo, but also execute a playbook with the extra --ask-sudo-pass / -K option so that Ansible asks you for the sudo password. However, you can also have very specific control over how and when sudo is used in a playbook.

I have a playbook with a few roles which I use to bootstrap a new debian server. It installs software, sets up ssh, sets up sudo and places a few config files. It is organized in roles, the main playbook looks like this:

As you can see, I have a few playbooks run with sudo on, and a few with sudo off. The git-setup, vim, screen and bash playbooks all do basically the same, they install software and place a configuration file. However, if the entire playbook is run as root, the configuration files placed would be owned by root. If the playbook is not run via sudo, the software cannot be installed.

Note that in the first case Ansible also supports setting file permissions on files. This however is not the case when configuration files are cloned from a git repository. The git module does not support setting permissions, and I don't like recursive chmod's.

This playbook makes sure both vim and git are installed. It uses sudo for that action. It then clones the git repository with my personal dotfiles, without using sudo. If this action would use sudo, the git repository in my home folder would me owned by root and I could not update it later on without using sudo. The last action symlinks the .vimrc file from the repo to the correct location. If that would be done with sudo I could not remove the file without root access.

If you define a role with sudo, like in the above example the postfix role, then you can use the sudo: no option in that playbook to make sure one or more actions are not executed with sudo.